/* * GRUB -- GRand Unified Bootloader * Copyright (C) 1999,2000,2001,2002,2003 Free Software Foundation, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* * Note: These functions defined in this file may be called from C. * Be careful of that you must not modify some registers. Quote * from gcc-2.95.2/gcc/config/i386/i386.h: 1 for registers not available across function calls. These must include the FIXED_REGISTERS and also any registers that can be used without being saved. The latter must include the registers where values are returned and the register where structure-value addresses are passed. Aside from that, you can include as many other registers as you like. ax,dx,cx,bx,si,di,bp,sp,st,st1,st2,st3,st4,st5,st6,st7,arg { 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 } */ /* * Note: GRUB is compiled with the options -mrtd and -mregparm=3. * So the first three arguments are passed in %eax, %edx, and %ecx, * respectively, and if a function has a fixed number of arguments * and the number if greater than three, the function must return * with "ret $N" where N is ((the number of arguments) - 3) * 4. */ #include #include #include #include #include #include #include #include #include #define ABS(x) ((x) - EXT_C(start) + GRUB_BOOT_MACHINE_KERNEL_ADDR + 0x200) .file "startup.S" .text /* Tell GAS to generate 16-bit instructions so that this code works in real mode. */ .code16 .globl start, _start start: _start: /* * Guarantee that "main" is loaded at 0x0:0x8200. */ ljmp $0, $ABS(codestart) /* * Compatibility version number * * These MUST be at byte offset 6 and 7 of the executable * DO NOT MOVE !!! */ . = EXT_C(start) + 0x6 .byte GRUB_BOOT_VERSION_MAJOR, GRUB_BOOT_VERSION_MINOR /* * This is a special data area 8 bytes from the beginning. */ . = EXT_C(start) + 0x8 VARIABLE(grub_total_module_size) .long 0 VARIABLE(grub_kernel_image_size) .long 0 VARIABLE(grub_compressed_size) .long 0 VARIABLE(grub_install_dos_part) .long 0xFFFFFFFF VARIABLE(grub_install_bsd_part) .long 0xFFFFFFFF VARIABLE(grub_prefix) .string "/boot/grub" /* * Leave some breathing room for the prefix. */ . = EXT_C(start) + 0x50 /* the real mode code continues... */ codestart: cli /* we're not safe here! */ /* set up %ds, %ss, and %es */ xorw %ax, %ax movw %ax, %ds movw %ax, %ss movw %ax, %es /* set up the real mode/BIOS stack */ movl $GRUB_MEMORY_MACHINE_REAL_STACK, %ebp movl %ebp, %esp sti /* we're safe again */ /* save boot drive reference */ ADDR32 movb %dl, EXT_C(grub_boot_drive) /* reset disk system (%ah = 0) */ int $0x13 /* transition to protected mode */ DATA32 call real_to_prot /* The ".code32" directive takes GAS out of 16-bit mode. */ .code32 incl %eax call EXT_C(grub_gate_a20) /* decompress the compressed part and put the result at 1MB */ movl $0x100000, %esi movl $(START_SYMBOL + GRUB_KERNEL_MACHINE_RAW_SIZE), %edi pushl %esi pushl EXT_C(grub_compressed_size) pushl %edi call lzo1x_decompress addl $12, %esp /* copy back the decompressed part */ movl %eax, %ecx cld rep movsb /* copy modules before cleaning out the bss */ movl EXT_C(grub_total_module_size), %ecx movl EXT_C(grub_kernel_image_size), %esi addl %ecx, %esi addl $START_SYMBOL, %esi decl %esi movl $END_SYMBOL, %edi addl %ecx, %edi decl %edi std rep movsb /* clean out the bss */ movl $BSS_START_SYMBOL, %edi /* compute the bss length */ movl $END_SYMBOL, %ecx subl %edi, %ecx /* clean out */ xorl %eax, %eax cld rep stosb /* * Call the start of main body of C code. */ call EXT_C(grub_main) /* * This is the area for all of the special variables. */ .p2align 2 /* force 4-byte alignment */ protstack: .long GRUB_MEMORY_MACHINE_PROT_STACK VARIABLE(grub_boot_drive) .long 0 VARIABLE(grub_start_addr) .long START_SYMBOL VARIABLE(grub_end_addr) .long END_SYMBOL VARIABLE(grub_apm_bios_info) .word 0 /* version */ .word 0 /* cseg */ .long 0 /* offset */ .word 0 /* cseg_16 */ .word 0 /* dseg_16 */ .word 0 /* cseg_len */ .word 0 /* cseg_16_len */ .word 0 /* dseg_16_len */ /* * This is the Global Descriptor Table * * An entry, a "Segment Descriptor", looks like this: * * 31 24 19 16 7 0 * ------------------------------------------------------------ * | | |B| |A| | | |1|0|E|W|A| | * | BASE 31..24 |G|/|0|V| LIMIT |P|DPL| TYPE | BASE 23:16 | * | | |D| |L| 19..16| | |1|1|C|R|A| | * ------------------------------------------------------------ * | | | * | BASE 15..0 | LIMIT 15..0 | * | | | * ------------------------------------------------------------ * * Note the ordering of the data items is reversed from the above * description. */ .p2align 2 /* force 4-byte alignment */ gdt: .word 0, 0 .byte 0, 0, 0, 0 /* code segment */ .word 0xFFFF, 0 .byte 0, 0x9A, 0xCF, 0 /* data segment */ .word 0xFFFF, 0 .byte 0, 0x92, 0xCF, 0 /* 16 bit real mode CS */ .word 0xFFFF, 0 .byte 0, 0x9E, 0, 0 /* 16 bit real mode DS */ .word 0xFFFF, 0 .byte 0, 0x92, 0, 0 /* this is the GDT descriptor */ gdtdesc: .word 0x27 /* limit */ .long gdt /* addr */ /* * These next two routines, "real_to_prot" and "prot_to_real" are structured * in a very specific way. Be very careful when changing them. * * NOTE: Use of either one messes up %eax and %ebp. */ real_to_prot: .code16 cli /* load the GDT register */ DATA32 ADDR32 lgdt gdtdesc /* turn on protected mode */ movl %cr0, %eax orl $GRUB_MEMORY_MACHINE_CR0_PE_ON, %eax movl %eax, %cr0 /* jump to relocation, flush prefetch queue, and reload %cs */ DATA32 ljmp $GRUB_MEMORY_MACHINE_PROT_MODE_CSEG, $protcseg .code32 protcseg: /* reload other segment registers */ movw $GRUB_MEMORY_MACHINE_PROT_MODE_DSEG, %ax movw %ax, %ds movw %ax, %es movw %ax, %fs movw %ax, %gs movw %ax, %ss /* put the return address in a known safe location */ movl (%esp), %eax movl %eax, GRUB_MEMORY_MACHINE_REAL_STACK /* get protected mode stack */ movl protstack, %eax movl %eax, %esp movl %eax, %ebp /* get return address onto the right stack */ movl GRUB_MEMORY_MACHINE_REAL_STACK, %eax movl %eax, (%esp) /* zero %eax */ xorl %eax, %eax /* return on the old (or initialized) stack! */ ret prot_to_real: /* just in case, set GDT */ lgdt gdtdesc /* save the protected mode stack */ movl %esp, %eax movl %eax, protstack /* get the return address */ movl (%esp), %eax movl %eax, GRUB_MEMORY_MACHINE_REAL_STACK /* set up new stack */ movl $GRUB_MEMORY_MACHINE_REAL_STACK, %eax movl %eax, %esp movl %eax, %ebp /* set up segment limits */ movw $GRUB_MEMORY_MACHINE_PSEUDO_REAL_DSEG, %ax movw %ax, %ds movw %ax, %es movw %ax, %fs movw %ax, %gs movw %ax, %ss /* this might be an extra step */ /* jump to a 16 bit segment */ ljmp $GRUB_MEMORY_MACHINE_PSEUDO_REAL_CSEG, $tmpcseg tmpcseg: .code16 /* clear the PE bit of CR0 */ movl %cr0, %eax andl $(~GRUB_MEMORY_MACHINE_CR0_PE_ON), %eax movl %eax, %cr0 /* flush prefetch queue, reload %cs */ DATA32 ljmp $0, $realcseg realcseg: /* we are in real mode now * set up the real mode segment registers : DS, SS, ES */ /* zero %eax */ xorl %eax, %eax movw %ax, %ds movw %ax, %es movw %ax, %fs movw %ax, %gs movw %ax, %ss /* restore interrupts */ sti /* return on new stack! */ DATA32 ret .code32 /* * grub_gate_a20(int on) * * Gate address-line 20 for high memory. * * This routine is probably overconservative in what it does, but so what? * * It also eats any keystrokes in the keyboard buffer. :-( */ FUNCTION(grub_gate_a20) movl %eax, %ecx call gloop1 movb $0xd1, %al outb $0x64 gloopint1: inb $0x64 andb $0x02, %al jnz gloopint1 movb $0xdd, %al testl %ecx, %ecx jz gdoit orb $0x02, %al gdoit: outb $0x60 call gloop1 /* output a dummy command (USB keyboard hack) */ movb $0xff, %al outb $0x64 call gloop1 ret gloop1: inb $0x64 andb $0x02, %al jnz gloop1 gloop2: inb $0x64 andb $0x01, %al jz gloop2ret inb $0x60 jmp gloop2 gloop2ret: ret #include "lzo1x.S" /* * This call is special... it never returns... in fact it should simply * hang at this point! */ FUNCTION(grub_stop) call prot_to_real /* * This next part is sort of evil. It takes advantage of the * byte ordering on the x86 to work in either 16-bit or 32-bit * mode, so think about it before changing it. */ FUNCTION(grub_hard_stop) hlt jmp EXT_C(grub_hard_stop) /* * grub_stop_floppy() * * Stop the floppy drive from spinning, so that other software is * jumped to with a known state. */ FUNCTION(grub_stop_floppy) movw $0x3F2, %dx xorb %al, %al outb %al, %dx ret /* * grub_reboot() * * Reboot the system. At the moment, rely on BIOS. */ FUNCTION(grub_reboot) call prot_to_real .code16 /* cold boot */ movw $0x0472, %di movw %ax, (%di) ljmp $0xFFFF, $0x0000 .code32 /* * grub_halt(int no_apm) * * Halt the system, using APM if possible. If NO_APM is true, don't use * APM even if it is available. */ FUNCTION(grub_halt) /* see if zero */ testl %eax, %eax jnz EXT_C(grub_stop) call prot_to_real .code16 /* detect APM */ movw $0x5300, %ax xorw %bx, %bx int $0x15 jc EXT_C(grub_hard_stop) /* don't check %bx for buggy BIOSes... */ /* disconnect APM first */ movw $0x5304, %ax xorw %bx, %bx int $0x15 /* connect APM */ movw $0x5301, %ax xorw %bx, %bx int $0x15 jc EXT_C(grub_hard_stop) /* set APM protocol level - 1.1 or bust. (this covers APM 1.2 also) */ movw $0x530E, %ax xorw %bx, %bx movw $0x0101, %cx int $0x15 jc EXT_C(grub_hard_stop) /* set the power state to off */ movw $0x5307, %ax movw $1, %bx movw $3, %cx int $0x15 /* shouldn't reach here */ jmp EXT_C(grub_hard_stop) .code32 /* * void grub_chainloader_real_boot (int drive, void *part_addr) * * This starts another boot loader. */ FUNCTION(grub_chainloader_real_boot) pushl %edx pushl %eax call EXT_C(grub_dl_unload_all) /* set up to pass boot drive */ popl %edx /* ESI must point to a partition table entry */ popl %esi /* Turn off Gate A20 */ xorl %eax, %eax call EXT_C(grub_gate_a20) call prot_to_real .code16 ljmp $0, $GRUB_MEMORY_MACHINE_BOOT_LOADER_ADDR .code32 /* * void grub_linux_boot_zimage (void) */ VARIABLE(grub_linux_prot_size) .long 0 VARIABLE(grub_linux_tmp_addr) .long 0 VARIABLE(grub_linux_real_addr) .long 0 FUNCTION(grub_linux_boot_zimage) /* copy the kernel */ movl EXT_C(grub_linux_prot_size), %ecx addl $3, %ecx shrl $2, %ecx movl $GRUB_LINUX_BZIMAGE_ADDR, %esi movl $GRUB_LINUX_ZIMAGE_ADDR, %edi cld rep movsl FUNCTION(grub_linux_boot_bzimage) call EXT_C(grub_dl_unload_all) movl EXT_C(grub_linux_real_addr), %ebx /* copy the real mode code */ movl EXT_C(grub_linux_tmp_addr), %esi movl %ebx, %edi movl $GRUB_LINUX_SETUP_MOVE_SIZE, %ecx cld rep movsb /* change %ebx to the segment address */ shrl $4, %ebx movl %ebx, %eax addl $0x20, %eax movw %ax, linux_setup_seg /* XXX new stack pointer in safe area for calling functions */ movl $0x4000, %esp call EXT_C(grub_stop_floppy) /* final setup for linux boot */ call prot_to_real .code16 cli movw %bx, %ss movw $GRUB_LINUX_SETUP_STACK, %sp movw %bx, %ds movw %bx, %es movw %bx, %fs movw %bx, %gs /* ljmp */ .byte 0xea .word 0 linux_setup_seg: .word 0 .code32 /* * This starts the multiboot kernel. */ FUNCTION(grub_multiboot_real_boot) /* Push the entry address on the stack. */ pushl %eax /* Move the address of the multiboot information structure to ebx. */ movl %edx,%ebx /* Unload all modules and stop the floppy driver. */ call EXT_C(grub_dl_unload_all) call EXT_C(grub_stop_floppy) /* Interrupts should be disabled. */ cli /* Move the magic value into eax and jump to the kernel. */ movl $GRUB_MB_MAGIC2,%eax popl %ecx jmp *%ecx /* * int grub_biosdisk_rw_int13_extensions (int ah, int drive, void *dap) * * Call IBM/MS INT13 Extensions (int 13 %ah=AH) for DRIVE. DAP * is passed for disk address packet. If an error occurs, return * non-zero, otherwise zero. */ FUNCTION(grub_biosdisk_rw_int13_extensions) pushl %ebp pushl %esi /* compute the address of disk_address_packet */ movw %cx, %si xorw %cx, %cx shrl $4, %ecx /* save the segment to cx */ /* ah */ movb %al, %dh /* enter real mode */ call prot_to_real .code16 movb %dh, %ah movw %cx, %ds int $0x13 /* do the operation */ movb %ah, %dl /* save return value */ /* clear the data segment */ xorw %ax, %ax movw %ax, %ds /* back to protected mode */ DATA32 call real_to_prot .code32 movb %dl, %al /* return value in %eax */ popl %esi popl %ebp ret /* * int grub_biosdisk_rw_standard (int ah, int drive, int coff, int hoff, * int soff, int nsec, int segment) * * Call standard and old INT13 (int 13 %ah=AH) for DRIVE. Read/write * NSEC sectors from COFF/HOFF/SOFF into SEGMENT. If an error occurs, * return non-zero, otherwise zero. */ FUNCTION(grub_biosdisk_rw_standard) pushl %ebp movl %esp, %ebp pushl %ebx pushl %edi pushl %esi /* set up CHS information */ /* set %ch to low eight bits of cylinder */ xchgb %cl, %ch /* set bits 6-7 of %cl to high two bits of cylinder */ shlb $6, %cl /* set bits 0-5 of %cl to sector */ addb 0xc(%ebp), %cl /* set %dh to head */ movb 0x8(%ebp), %dh /* set %ah to AH */ movb %al, %ah /* set %al to NSEC */ movb 0x10(%ebp), %al /* save %ax in %di */ movw %ax, %di /* save SEGMENT in %bx */ movw 0x14(%ebp), %bx /* enter real mode */ call prot_to_real .code16 movw %bx, %es xorw %bx, %bx movw $3, %si /* attempt at least three times */ 1: movw %di, %ax int $0x13 /* do the operation */ jnc 2f /* check if successful */ movb %ah, %bl /* save return value */ /* if fail, reset the disk system */ xorw %ax, %ax int $0x13 decw %si cmpw $0, %si je 2f xorb %bl, %bl jmp 1b /* retry */ 2: /* back to protected mode */ DATA32 call real_to_prot .code32 movb %bl, %al /* return value in %eax */ popl %esi popl %edi popl %ebx popl %ebp ret $(4 * 4) /* * int grub_biosdisk_check_int13_extensions (int drive) * * Check if LBA is supported for DRIVE. If it is supported, then return * the major version of extensions, otherwise zero. */ FUNCTION(grub_biosdisk_check_int13_extensions) pushl %ebp pushl %ebx /* drive */ movb %al, %dl /* enter real mode */ call prot_to_real .code16 movb $0x41, %ah movw $0x55aa, %bx int $0x13 /* do the operation */ /* check the result */ jc 1f cmpw $0xaa55, %bx jne 1f movb %ah, %bl /* save the major version into %bl */ /* check if AH=0x42 is supported */ andw $1, %cx jnz 2f 1: xorb %bl, %bl 2: /* back to protected mode */ DATA32 call real_to_prot .code32 movb %bl, %al /* return value in %eax */ popl %ebx popl %ebp ret /* * int grub_biosdisk_get_diskinfo_int13_extensions (int drive, void *drp) * * Return the geometry of DRIVE in a drive parameters, DRP. If an error * occurs, then return non-zero, otherwise zero. */ FUNCTION(grub_biosdisk_get_diskinfo_int13_extensions) pushl %ebp pushl %ebx pushl %esi /* compute the address of drive parameters */ movw %dx, %si xorw %dx, %dx shrl $4, %edx movw %dx, %bx /* save the segment into %bx */ /* drive */ movb %al, %dl /* enter real mode */ call prot_to_real .code16 movb $0x48, %ah movw %bx, %ds int $0x13 /* do the operation */ movb %ah, %bl /* save return value in %bl */ /* clear the data segment */ xorw %ax, %ax movw %ax, %ds /* back to protected mode */ DATA32 call real_to_prot .code32 movb %bl, %al /* return value in %eax */ popl %esi popl %ebx popl %ebp ret /* * int grub_biosdisk_get_diskinfo_standard (int drive, * unsigned long *cylinders, * unsigned long *heads, * unsigned long *sectors) * * Return the geometry of DRIVE in CYLINDERS, HEADS and SECTORS. If an * error occurs, then return non-zero, otherwise zero. */ FUNCTION(grub_biosdisk_get_diskinfo_standard) pushl %ebp pushl %ebx pushl %edi /* push CYLINDERS */ pushl %edx /* push HEADS */ pushl %ecx /* SECTORS is on the stack */ /* drive */ movb %al, %dl /* enter real mode */ call prot_to_real .code16 movb $0x8, %ah int $0x13 /* do the operation */ /* check if successful */ testb %ah, %ah jnz 1f /* bogus BIOSes may not return an error number */ testb $0x3f, %cl /* 0 sectors means no disk */ jnz 1f /* if non-zero, then succeed */ /* XXX 0x60 is one of the unused error numbers */ movb $0x60, %ah 1: movb %ah, %bl /* save return value in %bl */ /* back to protected mode */ DATA32 call real_to_prot .code32 /* pop HEADS */ popl %edi movb %dh, %al incl %eax /* the number of heads is counted from zero */ movl %eax, (%edi) /* pop CYLINDERS */ popl %edi movb %ch, %al movb %cl, %ah shrb $6, %ah /* the number of cylinders is counted from zero */ incl %eax movl %eax, (%edi) /* SECTORS */ movl 0x10(%esp), %edi andb $0x3f, %cl movzbl %cl, %eax movl %eax, (%edi) xorl %eax, %eax movb %bl, %al /* return value in %eax */ popl %edi popl %ebx popl %ebp ret $4 /* * int grub_biosdisk_get_num_floppies (void) */ FUNCTION(grub_biosdisk_get_num_floppies) pushl %ebp xorl %edx, %edx call prot_to_real .code16 /* reset the disk system first */ int $0x13 1: stc /* call GET DISK TYPE */ movb $0x15, %ah int $0x13 jc 2f /* check if this drive exists */ testb $0x3, %ah jz 2f incb %dl cmpb $2, %dl jne 1b 2: DATA32 call real_to_prot .code32 movl %edx, %eax popl %ebp ret /* * * grub_get_memsize(i) : return the memory size in KB. i == 0 for conventional * memory, i == 1 for extended memory * BIOS call "INT 12H" to get conventional memory size * BIOS call "INT 15H, AH=88H" to get extended memory size * Both have the return value in AX. * */ FUNCTION(grub_get_memsize) pushl %ebp movl %eax, %edx call prot_to_real /* enter real mode */ .code16 testl %edx, %edx jnz xext int $0x12 jmp xdone xext: movb $0x88, %ah int $0x15 xdone: movw %ax, %dx DATA32 call real_to_prot .code32 movw %dx, %ax popl %ebp ret /* * * grub_get_eisa_mmap() : return packed EISA memory map, lower 16 bits is * memory between 1M and 16M in 1K parts, upper 16 bits is * memory above 16M in 64K parts. If error, return zero. * BIOS call "INT 15H, AH=E801H" to get EISA memory map, * AX = memory between 1M and 16M in 1K parts. * BX = memory above 16M in 64K parts. * */ FUNCTION(grub_get_eisa_mmap) pushl %ebp pushl %ebx call prot_to_real /* enter real mode */ .code16 movw $0xe801, %ax int $0x15 shll $16, %ebx movw %ax, %bx DATA32 call real_to_prot .code32 cmpb $0x86, %bh je xnoteisa movl %ebx, %eax xnoteisa: popl %ebx popl %ebp ret /* * * grub_get_mmap_entry(addr, cont) : address and old continuation value (zero to * start), for the Query System Address Map BIOS call. * * Sets the first 4-byte int value of "addr" to the size returned by * the call. If the call fails, sets it to zero. * * Returns: new (non-zero) continuation value, 0 if done. */ FUNCTION(grub_get_mmap_entry) pushl %ebp pushl %ebx pushl %edi pushl %esi /* push ADDR */ pushl %eax /* place address (+4) in ES:DI */ addl $4, %eax movl %eax, %edi andl $0xf, %edi shrl $4, %eax movl %eax, %esi /* set continuation value */ movl %edx, %ebx /* set default maximum buffer size */ movl $0x14, %ecx /* set EDX to 'SMAP' */ movl $0x534d4150, %edx call prot_to_real /* enter real mode */ .code16 movw %si, %es movl $0xe820, %eax int $0x15 DATA32 jc xnosmap cmpl $0x534d4150, %eax jne xnosmap cmpl $0x14, %ecx jl xnosmap cmpl $0x400, %ecx jg xnosmap jmp xsmap xnosmap: xorl %ecx, %ecx xsmap: DATA32 call real_to_prot .code32 /* write length of buffer (zero if error) into ADDR */ popl %eax movl %ecx, (%eax) /* set return value to continuation */ movl %ebx, %eax popl %esi popl %edi popl %ebx popl %ebp ret /* * void grub_console_real_putchar (int c) * * Put the character C on the console. Because GRUB wants to write a * character with an attribute, this implementation is a bit tricky. * If C is a control character (CR, LF, BEL, BS), use INT 10, AH = 0Eh * (TELETYPE OUTPUT). Otherwise, save the original position, put a space, * save the current position, restore the original position, write the * character and the attribute, and restore the current position. * * The reason why this is so complicated is that there is no easy way to * get the height of the screen, and the TELETYPE OUPUT BIOS call doesn't * support setting a background attribute. */ FUNCTION(grub_console_real_putchar) movl %eax, %edx pusha movb EXT_C(grub_console_cur_color), %bl call prot_to_real .code16 movb %dl, %al xorb %bh, %bh /* use teletype output if control character */ cmpb $0x7, %al je 1f cmpb $0x8, %al je 1f cmpb $0xa, %al je 1f cmpb $0xd, %al je 1f /* save the character and the attribute on the stack */ pushw %ax pushw %bx /* get the current position */ movb $0x3, %ah int $0x10 /* check the column with the width */ cmpb $79, %dl jl 2f /* print CR and LF, if next write will exceed the width */ movw $0x0e0d, %ax int $0x10 movb $0x0a, %al int $0x10 /* get the current position */ movb $0x3, %ah int $0x10 2: /* restore the character and the attribute */ popw %bx popw %ax /* write the character with the attribute */ movb $0x9, %ah movw $1, %cx int $0x10 /* move the cursor forward */ incb %dl movb $0x2, %ah int $0x10 jmp 3f 1: movw $1, %bx movb $0xe, %ah int $0x10 3: DATA32 call real_to_prot .code32 popa ret /* * int grub_console_getkey (void) * BIOS call "INT 16H Function 00H" to read character from keyboard * Call with %ah = 0x0 * Return: %ah = keyboard scan code * %al = ASCII character */ /* this table is used in translate_keycode below */ translation_table: .word GRUB_CONSOLE_KEY_LEFT, 2 .word GRUB_CONSOLE_KEY_RIGHT, 6 .word GRUB_CONSOLE_KEY_UP, 16 .word GRUB_CONSOLE_KEY_DOWN, 14 .word GRUB_CONSOLE_KEY_HOME, 1 .word GRUB_CONSOLE_KEY_END, 5 .word GRUB_CONSOLE_KEY_DC, 4 .word GRUB_CONSOLE_KEY_BACKSPACE, 8 .word GRUB_CONSOLE_KEY_PPAGE, 7 .word GRUB_CONSOLE_KEY_NPAGE, 3 .word 0 /* * translate_keycode translates the key code %dx to an ascii code. */ .code16 translate_keycode: pushw %bx pushw %si movw $ABS(translation_table), %si 1: lodsw /* check if this is the end */ testw %ax, %ax jz 2f /* load the ascii code into %ax */ movw %ax, %bx lodsw /* check if this matches the key code */ cmpw %bx, %dx jne 1b /* translate %dx, if successful */ movw %ax, %dx 2: popw %si popw %bx ret .code32 FUNCTION(grub_console_getkey) pushl %ebp call prot_to_real .code16 int $0x16 movw %ax, %dx /* real_to_prot uses %eax */ call translate_keycode DATA32 call real_to_prot .code32 movw %dx, %ax popl %ebp ret /* * int grub_console_checkkey (void) * if there is a character pending, return it; otherwise return -1 * BIOS call "INT 16H Function 01H" to check whether a character is pending * Call with %ah = 0x1 * Return: * If key waiting to be input: * %ah = keyboard scan code * %al = ASCII character * Zero flag = clear * else * Zero flag = set */ FUNCTION(grub_console_checkkey) pushl %ebp xorl %edx, %edx call prot_to_real /* enter real mode */ .code16 movb $0x1, %ah int $0x16 jz notpending movw %ax, %dx DATA32 jmp pending notpending: decl %edx pending: DATA32 call real_to_prot .code32 movl %edx, %eax popl %ebp ret /* * grub_uint16_t grub_console_getxy (void) * BIOS call "INT 10H Function 03h" to get cursor position * Call with %ah = 0x03 * %bh = page * Returns %ch = starting scan line * %cl = ending scan line * %dh = row (0 is top) * %dl = column (0 is left) */ FUNCTION(grub_console_getxy) pushl %ebp pushl %ebx /* save EBX */ call prot_to_real .code16 xorb %bh, %bh /* set page to 0 */ movb $0x3, %ah int $0x10 /* get cursor position */ DATA32 call real_to_prot .code32 movb %dl, %ah movb %dh, %al popl %ebx popl %ebp ret /* * void grub_console_gotoxy(grub_uint8_t x, grub_uint8_t y) * BIOS call "INT 10H Function 02h" to set cursor position * Call with %ah = 0x02 * %bh = page * %dh = row (0 is top) * %dl = column (0 is left) */ FUNCTION(grub_console_gotoxy) pushl %ebp pushl %ebx /* save EBX */ movb %dl, %dh /* %dh = y */ movb %al, %dl /* %dl = x */ call prot_to_real .code16 xorb %bh, %bh /* set page to 0 */ movb $0x2, %ah int $0x10 /* set cursor position */ DATA32 call real_to_prot .code32 popl %ebx popl %ebp ret /* * void grub_console_cls (void) * BIOS call "INT 10H Function 09h" to write character and attribute * Call with %ah = 0x09 * %al = (character) * %bh = (page number) * %bl = (attribute) * %cx = (number of times) */ FUNCTION(grub_console_cls) pushl %ebp pushl %ebx /* save EBX */ call prot_to_real .code16 /* move the cursor to the beginning */ movb $0x02, %ah xorb %bh, %bh xorw %dx, %dx int $0x10 /* write spaces to the entire screen */ movw $0x0920, %ax movw $0x07, %bx movw $(80 * 25), %cx int $0x10 /* move back the cursor */ movb $0x02, %ah int $0x10 DATA32 call real_to_prot .code32 popl %ebx popl %ebp ret /* * void grub_console_setcursor (int on) * BIOS call "INT 10H Function 01h" to set cursor type * Call with %ah = 0x01 * %ch = cursor starting scanline * %cl = cursor ending scanline */ console_cursor_state: .byte 1 console_cursor_shape: .word 0 FUNCTION(grub_console_setcursor) pushl %ebp pushl %ebx /* push ON */ pushl %eax /* check if the standard cursor shape has already been saved */ movw console_cursor_shape, %ax testw %ax, %ax jne 1f call prot_to_real .code16 movb $0x03, %ah xorb %bh, %bh int $0x10 DATA32 call real_to_prot .code32 movw %cx, console_cursor_shape 1: /* set %cx to the designated cursor shape */ movw $0x2000, %cx popl %eax testl %eax, %eax jz 2f movw console_cursor_shape, %cx 2: call prot_to_real .code16 movb $0x1, %ah int $0x10 DATA32 call real_to_prot .code32 popl %ebx popl %ebp ret /* * grub_getrtsecs() * if a seconds value can be read, read it and return it (BCD), * otherwise return 0xFF * BIOS call "INT 1AH Function 02H" to check whether a character is pending * Call with %ah = 0x2 * Return: * If RT Clock can give correct values * %ch = hour (BCD) * %cl = minutes (BCD) * %dh = seconds (BCD) * %dl = daylight savings time (00h std, 01h daylight) * Carry flag = clear * else * Carry flag = set * (this indicates that the clock is updating, or * that it isn't running) */ FUNCTION(grub_getrtsecs) pushl %ebp call prot_to_real /* enter real mode */ .code16 clc movb $0x2, %ah int $0x1a DATA32 jnc gottime movb $0xff, %dh gottime: DATA32 call real_to_prot .code32 movb %dh, %al popl %ebp ret /* * grub_get_rtc() * return the real time in ticks, of which there are about * 18-20 per second */ FUNCTION(grub_get_rtc) pushl %ebp call prot_to_real /* enter real mode */ .code16 /* %ax is already zero */ int $0x1a DATA32 call real_to_prot .code32 movl %ecx, %eax shll $16, %eax movw %dx, %ax popl %ebp ret /* * unsigned char grub_vga_set_mode (unsigned char mode) */ FUNCTION(grub_vga_set_mode) pushl %ebp pushl %ebx movl %eax, %ecx call prot_to_real .code16 /* get current mode */ xorw %bx, %bx movb $0x0f, %ah int $0x10 movb %al, %dl /* set the new mode */ movb %cl, %al xorb %ah, %ah int $0x10 DATA32 call real_to_prot .code32 movb %dl, %al popl %ebx popl %ebp ret /* * unsigned char *grub_vga_get_font (void) */ FUNCTION(grub_vga_get_font) pushl %ebp pushl %ebx call prot_to_real .code16 movw $0x1130, %ax movb $0x06, %bh int $0x10 movw %es, %bx movw %bp, %dx DATA32 call real_to_prot .code32 movzwl %bx, %ecx shll $4, %ecx movw %dx, %ax addl %ecx, %eax popl %ebx popl %ebp ret